Ring stick and finger sizers, plastic (both items together)

Finger sizers (for measuring the size of fingers) sizes A to Z plus extra-large sizes up to Z+6 (32 sizes in all)

and

Ring stick (for measuring the size of rings). 

Both in a tasteful blue.

These are not the bargain-basement models, they are of a decent thickness and do not break easily.  However, they are very cheap, quite good to give away to a customer who wants to measure their partner's finger, good for very occasional use on a market stall, not good enough for regular use in a shop.